The present invention generally relates to lighting devices (e.g., flashlights) and, more particularly, to a portable lighting device having an adjustable and highly uniform spotlight beam.
Portable lighting devices, commonly known as flashlights or lanterns, have been commercially available for many years. A typical flashlight is generally made using a light source, such as an incandescent lamp, a reflector, a lens, and a power source, such as one or more dry cell alkaline batteries. The lens is generally disposed forward of the light source and reflector at the outlet. In some conventional flashlights, the lamp is axially movable towards or away from the reflector to adjust the spot size of the resultant light beam.
The spotlight beam produced by a conventional flashlight is typically non-uniform in intensity and geometry. While an adjustable lamp and reflector focus arrangement is well suited to adjust size of the resultant illuminating spotlight beam, the overall geometric shape and non-uniform light intensity generally remains. The poor uniformity of the light beam intensity and geometry detracts from the overall effectiveness and usefulness of the lighting device.
In view of these disadvantages, it would be desirable to have a portable lighting device that produces a spotlight beam of high uniform intensity and geometry. It is further desirable to provide for a lighting device having an adjustable size spotlight beam of high uniform intensity.